Java 示例 - 集合删除

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  问题描述

  如何从集合中删除特定元素？
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  解决方案

  以下示例演示了如何借助 Collection 类的 collection.remove() 方法从集合中删除某个元素。

  
  import java.util.*;
  public class CollectionTest {
     public static void main(String [] args) {   
        System.out.println( "Collection Example!\n" ); 
        int size;
        HashSet <String>collection = new HashSet <String>();
        String str1 = "Yellow", str2 = "White", str3 = "Green", str4 = "Blue";  
        Iterator iterator;
        collection.add(str1);    
        collection.add(str2);   
        collection.add(str3);   
        collection.add(str4);
        System.out.print("Collection data: ");  
        iterator = collection.iterator();     
        
        while (iterator.hasNext()){
           System.out.print(iterator.next() + " ");  
        }
        System.out.println();
        collection.remove(str2);
        System.out.println("After removing [" + str2 + "]\n");
        System.out.print("Now collection data: ");
        iterator = collection.iterator();     
        
        while (iterator.hasNext()){
           System.out.print(iterator.next() + " ");  
        }
        System.out.println();
        size = collection.size();
        System.out.println("Collection size: " + size + "\n");
     }
  }
  

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  结果

  上面的代码示例将产生以下结果。

  
  Collection Example!
  Collection data: Blue White Green Yellow
  After removing [White]
  Now collection data: Blue Green Yellow
  Collection size: 3